General and specific word knowledge as predictors of children's categorization
There is a debate in the literature as to whether young children’s categorization abilities are more closely related to their general productive vocabulary or their specific word knowledge. The present study examines this relationship in children 18 to 26 months of age. Specifically, it tests the hypothesis that children’s understanding of individual words is more closely related to their category performance than the overall size of their productive vocabulary. Twenty children at 19 months (range= 18-20 months) and 25 months of age (range= 24-26 months) participated in the study. Children’s category performance was assessed using an object manipulation task with novel objects. Half of the children received novel names for the novel objects, and half did not. Two measures were then assessed: children’s knowledge of the novel names in a comprehension test, and children’s productive vocabulary outside of the laboratory, as measured by a parental checklist. Consistent with previous findings, the results indicate that children with larger productive vocabularies show more advanced categorizing. More importantly, however, the data suggest that children who received names for the novel objects outperformed children who did not receive the names, regardless of the size of their productive vocabulary. These findings suggest that hearing object names help children categorize objects, and may be a better predictor of children’s category performance than their productive vocabulary.